Abstract implementation of a lazy loaded list of (persistent) objects.
Needs to be extended to implement the

retrieveObjectForIndex()

method to retrieve
the object at the specified index from whatever datasource is being used, and to implement
the

getSize()

method to return the size of the list. The "datasource" could
be results for a query, or a connection to a datastore, or whatever ... just a source of objects.
TODO Change Localised message numbers to be generic